Audio production equipment includes meters or readouts whereby an operator can determine various conditions that are pertinent to processing of the signal content, quality and other concerns. The moving display of a meter can provide information that is useful for various purposes and not only for the assurance that there is a signal present. A meter can also provide a visual warning that the signal amplitude may be too high and may potentially cause clipping or distortion by overdriving audio amplifiers. The signal level may be low, potentially introducing hiss. Apart from signal amplitude, meters may be provided as indicators for other parameters, such as frequency spectrum, carrier modulation in a transmitter, etc. In this context, a “meter” might entail any of various changeable indicators such as movable pointers, a variable line of lamps or LEDs, changeable colors, and other indicating techniques.